There have been numerous examples of hydraulic hospital beds and medical procedure tables in the prior art. These devices use hydraulic cylinders to raise and lower the bed itself and the head and leg adjustment portions. Other hospital beds are electrically operated. In the case of electrically operated beds, disengagement of the mechanical drive member will allow quick lowering of head and leg portions in case of an emergency. Hydraulically operated beds generally have not had this capability because their rods usually are directly coupled to the head and leg portions, leading to a generally slow lowering rate, even in an emergency when cardiac-pulmonary resuscitation (CPR) might be required.
U.S. Pat. No. 4,038,709 shows a hospital bed that has a dual hydraulic system, operable by either compressed air or a manual foot pump. This bed does have a way to allow rapid lowering of the head and foot sections in an emergency, but it is mechanical.
U.S. Pat. No. 3,149,349 illustrates another design for a hydraulically driven hospital bed. U.S. Pat. No. 3,281,141 illustrates a hydraulically operated surgical table. The surgical table is powered by both an electrical pump and a foot operated pump. U.S Pat. No. 2,217,783 illustrates yet another hydraulically operated operating table. The operating table in this case has a dual pumping system for the hydraulic power, having both an electrical and hand operated pump. U.S. Pat. No. 4,559,655 illustrates an electrical operated hospital bed having a means to rapidly lower the head and foot portions in an emergency.